Refrigerating apparatus



Sept. 15, 1936. J G K|NG 2,054,328

.REFRIGERATING APPARATUS Original Filed March 31, 1923 2 Sheets-Sheet 1 Sept. 15, 1936. J G K 2,054,328

REFRIGERATING APPARATUS Original Filed March 31, 1923 2 Sheets-Sheet 2 Patented Sept. 15, 1936 PATENT ()FFICE REFRIGERATING APPARATUS Jesse G. King, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation, a corporation of Delaware Application March 31,

1928, Serial No. 266,284

Renewed August 10, 1934 19 Claims.

This invention relates to refrigerating systems and particularly to control mechanism therefor.

It is an object of the present invention to provide an improved refrigerating system in which a predetermined mean temperature is normally maintained by a control mechanism and to provide improved means for modifying the operation of the system so as to obtain temporarily a diiferent mean temperature of the cooling unit without disrupting the normal control mechanism One of the objects of the present invention is to provide a refrigerating system of the type in which a-control mechanism is provided for maintaining the cooling unit of the system between predetermined temperature limits and to provide an auxiliary control device which may be operated without disrupting the control mechanism to temporarily change the lower temperature limit of the unit for a plurality of cycles of operation without disrupting the upper temperature limit.

In carrying out these objects it is a further object to provide a refrigerating system including control mechanism which normally maintains a predetermined mean temperature of the cooling unit and to provide auxiliary control means which can be rendered operative and inoperative manually for temporarily modifying the temperature of the cooling unit without disrupting the normal control mechanism which auxiliary means also includes provisions for automatically modifying the temperature of the cooling unit and which is rendered inoperative after a predetermined modified temperature condition of the cooling unit for restoring the system to the normal control of the control means.

Referring to the drawings- Fig. 1 shows a refrigerating circuit embodying the improved control device of the invention.

Fig. 2 is a side view partly in section of a control device for the system of Fig. 1 said device being provided with the improved modifying means of the invention.

Fig. 3 is an illustration of the modifying device.

Fig. 4 shows the control device of the invention with the contacts about to open.

Fig. 5 illustrates the same in open position.

Fig. 6 is a curve illustrating normal operation of the refrigerating circuit.

Fig. 7 is'a curve showing normal operation with interposition of an abnormal cycle andsubsequent returnto normal.

Fig. 8 illustrates normal operation with abnormal operation continued for a desired length of time and a final return to normal.

In the mechanical type of refrigerator which is represented diagramatically by the refrigerating circuit shown in Fig. 1 it is desired to maintain normally a predetermined temperature in a cooling unit or refrigerating element such as that indicated by the evaporator l0 and its associated ducts i I. This element is supplied with a suitable refrigerant such as sulphur dioxide by means of a compressor i2 driven by a motor l3. The refrigerant after being passed thru a condenser 14 and collected in a receiver 15 is fed to the refrigerating element thru a pipe l6 and is withdrawn therefrom thru pipe I! and returned to the compressor. A suitable mechanism is provided for controlling the operation of the sys tem. This mechanism is herein shown for the purpose of illustrating the invention as a switch. This switch is connected into the suction side of the system as at i8 and is used to regulate the operation of the system. The control device is shown diagrammatically in Fig. 1 and comprises a flexible metal bellows i9 connected to the pipe I! and adapted by a lever system 20 to operate the switch 2| which controls the operation of the 25 motor.

In the system thus diagrammatically represented a predetermined temperature will normally be maintained in the refrigerating element I, H. However in some cases it is frequently desirable to obtain for a temporary period a different temperature and an arrangement is provided in which this temporary phase of operation may be secured at will.

Thus for example, whilethe refrigerating element l0, H may be adequate for cooling food to a certain degree and even freezing the same by prolonged exposure it may sometimes be desired to hasten the freezing process and an adjusting meanstis provided for modifying the control means so that it will render it possible to produce such hastening.

Referring in detail to the drawings, the control mechanism shown in Fig. 2 and diagrammatically indicated in Fig. 1 comprises a pressure operated device such as a switch which is arranged to make and break the circuit of the electric motor driving the compressor. The action of the pressure-controlled switch is modified by a resilient adjusting means which is normally set for cyclically producing a desired temperature in the refrigerating element and is also provided with an auxiliary adjusting means which operates independently of the first means and the function of which is to modify the action of the first means. The pressure responsive means consists of a hollow metallic bellows l9 which is sealed at the top by a plate 22 and which is connected at the bottom by means of pipe 23 to the refrigerating system circuit. An operating member or lever 24 pivoted at 25 is adapted to follow the movements of plate 22 since it is pivoted thereto as at 25.

- The operation of lever 24 causes the switch con- .tacts I25 and I26 to be brought in contact with each other or separated as shown in Figs. 4 and 5, and this operation is accomplished through the intermediary of connection levers 226 and 27, which are pivoted to the lever 24 and to the switch contact 25.

The snap action of the lever 24 is produced by a cam system comprising nose 28 and a hardened steel roller 29 which engages therewith. This structure is described in the copending application of Otto M. Summers, Serial No. 123,420, filed July 19, 1926; now Patent 1,802,486 dated April As the pressure builds up within the flexible metal bellows I9 the latter expands and since the lever 24 is pivoted at 25 to a portion of the frame 38 of the control device it is evident that the bellows will raise the operating lever24. The upward movement of the lever 24 is, however, resisted by a yieldable adjusting system comprising a coiled spring 3| operating against a plunger 32 and spring 3I held by a suitable housing 33, which latter provides a means for adjusting the tension of the spring 3| and, consequently, the force exerted against lever 24. A suitable anvil 34 is provided for the coaction of the plunger 32 against the lever 24. A spring 35 carried by a rod 36 attached to the lever beyond the point of its attachment to the bellows e. g., as at 34, is used for resisting the descent of the lever 24 when the pressure in the bellows I9 decreases.

It is apparent that the upward and downward movement of the lever 24 are effected with sudden snap actions due to the construction of cam 28 and roller 29, and the arrangement of the pivots so that the switch contacts I25, 428 are opened and closed suddenly thus preventing th drawing of arcs at these points.

The spring 35 and the resilient adjusting system composed of spring 3| and retaining cap 33 are preferably so adjusted as to produce what may be termed a normal predetermined temperature, that is, a temperature suitable for ordinary operation of the refrigerator.

This temperature may be suflicient to cool food stufis stored in the crypts of the refrigerating element or in the compartment cooled thereby and may be sufiicient to produce freezing if the food is exposed long enough to this temperature. However, if it should be decided to hasten the freezing .action it is apparent that the normal operation of the device must be modified in some manner so that the refrigerator is temporarily maintained at a lower temperature.

As the apparatus is adjusted at the factory by proper tensioning of the springs 35 and 3!, the lever 24 will have its upward and downward movements resisted in such a manner that it will, when pushed by the diaphragm I9, open and close the circuit of the driving motor I3 only at the maximum and minimum operating points at which it is set. It is apparent that by interposing a resistance to its downward movement the operation of the switch contacts will be resisted and that'the system will continue operating for a longer period of time thus prolonging the freezing cycle.

A suitable method of interposing such a resistance is illustrated in the embodiment of the present invention and consists in placing a resilient obstruction in the path of the downward movement of the lever 24, so that its movement is retarded by the tension of the spring interposed between the lever 24 and the frame of the apparatus.

The resilient blocking means used in the preferred embodiment of the invention comprises a lever system including a member 38 pivoted to link 39 which in turn is journaled in the stirrup 40 carried by the frame 4| of the control device.

The link 42 serves to connect the member 38 with a rod 43 which slides vertically in a guide in the frame M. A spring 44 is disposed intermediate the link 39 and the member 38. There is likewise provided a guide rod 45 having adjusting nuts 46 and 5| for adjusting the tension of the spring 44 with respect to its effect upon link 39 and member 38. It is, therefore, obvious that link 38 is resiliently pivoted on link 39 at the point 41. Member 38 is provided with a notch 48 which engages a pin 49 carried by the lever 24. It is apparent that this resilient blocking system may be pushed out of the way of the pin 49 so that the lever may move unhindered in an up and down direction and that the notch 48 may be snapped in engagement with pin 49 so that upon its downward movementthe lever 24- will drag member 38 down with it against the pressure of spring 44. This will impose a block or drag upon the lever 24, the intensity of which may be regulated by suitable tensioning of the spring 44.

The resilient blocking or modifying system just described is so arranged that normally it tends to lie out of the path of the descending pin 49 but it isevident that the resilient modifying system may be snapped into engagement with the pin. The result of this retardation of. downward descent of the lever will be to cause a prolongation of the freezing cycle, in other words, a' longer-than-normal operation of the compressor. Upon the ascent of the lever 24 the resilient system will fall out of the way and leave the control apparatus free-to function normally.

If it is decided, however, to'continue the modifying operation of the control device the resilient system above mentioned is snapped into place and lockedin place by turning the nut 50 to the extremity of the guide rod 43. The refrigerating system will then work continuously with modified prolonged freezing cycle and thus produce a more rapid freezing.

The various positions of the modifying device are shown in the drawings. In Fig. 2, the control mechanism is shown arranged for normal operation as. determined at the factory. In this case the resilient blocking or modifying device is shown lying in its inoperative position, out of the way .of pin 49 carried by lever 24. In Fig. 4 the modifying device is shown snapped into place with the switch contacts I25 and I28 closed. In

this position one prolonged cycle of operation or quick-freezing cycle will be produced and after the modifying device falls out of the way of the pin 49 as shown in Fig. 5, which will occur when the lever 24 ascends, the control device will return to its normal function. In Fig. 3 the modifying device is shown locked in position for producing a plurality of freezing cycles. These freezing cycles will continue until the modifying device is released by unscrewing the nut 50 and allowed to fall back out of the way of the plotted against cycles or time.

Fig. 6 represents normal cyclic operation. Fig. 7 shows the compressor operating phase of one cycle prolonged by the modifying means of the invention. Fig. 8 illustrates the compressor operating phases as prolonged for a plurality of cycles by the modifying apparatus.

In these graphs the points A represent the pressures at which the switch closes to start the apparatus, and B the points when the switch opens to stop the compressor. The points C represent the pressure temperature condition existingin the apparatus at the instant the switch opens after the same is affected by the modifying device. The one quick freezing cycle of Fig. '7 is produced by snapping the modifying device into operative position Upon the termination of the cycle the modifying device falls out of the way and the control switch resumes its normal cyclic operation. If the modifying device is locked in operative position by turning the nut 50, a succession of. quick-freezing cycles will be produced as shown by Fig. 8. By unscrewing the nut 50 the modifying device returns to its normal inoperative position.

From the "graphs it will be observed that the control is effected by changing the lower temperature limits and leaving the upper temperature limits unchanged. In this manner defrostin will occur at every'cycle.

By means of the arrangement shown a convenient means is provided for producing at will either a single quick freezing cycle or a plurality of such cycles and for restoring the system automatically to normal cyclic functioning after the single quick-freezing cycle has terminated.

'Means are also provided for manually restoring the system to normal cyclic operation upon the termination of any desired number of quickfreezing cycles- By virtue of this invention, if desired, defrosting of the cooling unit can be secured during each cycle. It is desirable in some instances that the cooling unit be free from frost. The control device in such a casecan be set so that the higher temperature limit is above the freezing point of water. In this manner, during each cycle of operation the frost which collects during the operation of the compressor is melted off. By means of the arrangement of the invention quick freezing can be effected without disturbing the upper temperature of the cooling unit since only the lower temperature range is affected. Thus, during quick freezing operations the lower temperature limit being changed, a lower mean temperature is obtained in the cooling unit while the upper temperature limit is maintained the same.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form it is to be understood that other forms may be adopted all coming within, the scope of the claims which follow.

What is claimed is as follows:

1. A pressure responsive switch means for a 75 refrigerating system including an electric circuit and pressure responsive means for opening and closing the electric circuit according to predetermined high and'low temperatures of the refrigerating system, a control means for temporarily causing the pressure responsive means to open and close the electric circuit at an altered set of temperature limits, said control means including means rendered effective by the operation of the pressure responsive means for restoring the normal operation of the pressure responsive means, and means for preventing the restoring of the pressure responsive means to normal operation.

2. A pressure responsive switch means for a refrigerating system including an electric circuit and pressure responsive means for opening and closing the electric circuit according to predetermined high and low temperatures of the refrigerating system, a control means for temporarily causing the pressure responsive means to open and close the electric circuit at an altered set of temperature limits, said control means including automatic means rendered effective by the operation of the pressure responsive means for restoring the normal operation of the pressure responsive means, and manually operable means for rendering ineffective the automatic means.

3. Switching mechanism including a member to be actuated, pressure responsive means including an operating member for said first mentioned member, resilient adjustable means for interposing a normal resistance to the operation of the operating member to cause it to normally operate within predetermined pressure limits, manually controllable means for temporarily interposing an additional resistance to the movement of the pressure responsive means, said manually controllable means including means rendered effective by the movement of the pressure responsive means for removing the additional resistance to the movement of the pressure responsive means, and means for preventing the removal of the additional resistance.

4. A control mechanism for refrigerators comprising a cyclically operated movable member having a given normal range,- means for securing cycles of operation having a diiferent range, manually controlled means for rendering said last means effective or ineffective, said manually controlled means being movable to one position for obtaining the cycles having a different range, and selectively operable means to prevent more than a single cycle of operation of said cyclically operated movable member at the different range.

5. A control mechanism comprising a cyclically operated movable member having a given normal range with given high and low limits, means for securing a plurality of successive cycles of the movable member having other temperature lim- .its, means for securing a single cycle of the movable member having other temperature limits and then returning the movable member to its normal range, and control means for controlling the means for securing cycles having other temperature limits.

6. For use with anautomatic control device having alternately oppositely movable member, means to prolong the movement of said movable member in one direction comprising a biased member to be engaged by said movable member,

and manually operable means, selective to either set and retain said biased member in position to be engaged by said movable member during the latter part only of its movement in such direction to prolong movement of the movable member during each alternate movement of the movable member or to cause such prolongation during but one of such movements.

7. For use with an automatic control device having an alternately oppositely movable member, means to prolong the movement of said movable member in one direction comprising a biased member to be engaged by said movable member, manually operable means to set and retain said biased member in position to be engaged by said movable member during the latter part only of its movement in such direction to prolong movement of the movable member durafter a single one of such movements.

8. A control mechanism comprising a cyclically operated movable member having a given normal range, means for securing a single cycle of the movable member having a prolonged movement in one direction, means for securing a plurality of successive cycles of the movable member having a prolonged movement in one direction, and manually actuated means for controlling both of said first two named means.

9. An automatic control device having an alternately oppositely movable member, means to prolong the movement of said movable member in one direction including means forming a modifying device, said device beingselectively operable to engage the movable member during the latter part only of its movement in such direction during each alternate movement of the movable member or during but one of such movements, and means for actuating said auxiliary means.

10. A control mechanism for refrigerators comferent range, and selectively operable means to set and retain the'manually controlled means to secure a plurality of cycles having a different range.

11. A control means including a pressure responsive means and means connected thereto for opening and closing an electric circuit, yielding means acting at all times directly upon the pressure responsive means to control the movement of the pressure responsive means, means for changing the pressure difierential between the opening and closing pressure limits, and a resilient buffer obstructing means movable into and out of the range of movement of the pressure responsive means for changing one of said pressure limits.

12. A control means including a pressure responsive means and means connected thereto for opening and closing an electric circuit, yielding means acting at all times directly upon the pressure responsive means to control the movement of the pressure responsive means, a resilient buffer means acting upon the pressure responsive means, and a second resilient buffer means acting independently of said first mentioned resilient bufier means upon the pressure responsive means.

13. A control means including a pressure responsive means and. means connected thereto for opening and closing an electric circuit, yielding means for controlling the movement of the pressure responsive means to cause the opening and closing of the electric circuit at predetermined pressure limits, said pressure responsive means being movable in a predetermined path, and an obstructing means movable into and out of the path of movement of the pressure responsive means in a direction transverse to the path of movement of the pressure responsive means for changing one of the pressure limits.

14. A control means including a pressure responsive means and means connected thereto for opening and closing an electric circuit, yielding means for controlling the movement of the pressure responsive means to cause the opening and closing of the electric circuit at predetermined pressure limits, said pressure responsive means being movable in a predetermined path, and an obstructing means movable into and out of the path of movement of the pressure responsive means in a direction transverse to the path of movement of the pressure responsive means for changing one of the pressure limits, said obstructing means including means for moving itself out of the path of movement of the pressure responsive means.

15. A control means including a pressure responsive means and means connected thereto for opening and closing an electric circuit, yielding means for controlling the movement of the pressure responsive means to cause the opening and closing of the electric circuit at predetermined pressure limits, said pressure responsive means being movable in a predetermined path, and an obstructing means movable into and out of the path of movement of the pressure responsive means in a direction transverse to the path of movement of the pressure responsive means for changing one of the pressure limits, and means for retaining the obstructing means in the path of movement of the pressure responsive means for successive cycles.

16. A control means including .a pressure responsive means and means operated by said pressure responsive means for opening and closing an electric circuit, a loading means for normally controlling the movement of the pressure responsive means to normally cause the opening and closing of the electric circuit at predetermined pressure limits, auxiliary means for disturbing said pressure limits for a single cycle and thereafter automatically returning the pressure limits to normal, and manual manipulating means operable at will for rendering said auxiliary means inefiective at any time desired.

17. A control means including a pressure responsive means and means operated by said pressure responsive means for opening and closing an electric circuit, a loading means for normally controlling the lnovement of the pressure responsive means to normally cause the opening and closing of the electric circuit at predetermined pressure limits, asingle cycle loading device for afiecting the loading of said pressure responsive means to disturb said pressure limits for a single cycle and then automatically returning to normal the loading of said pressure responsive means, and manual manipulating means operable at will for rendering said single cycle loading device ineifective at any time desired.

18. A control means including a pressure responsive means and means operated by said pressure responsive means for opening and closing an electric circuit, a loading means for normally controlling the movement of the pressure responsive means to normally cause the opening and closing of the electric circuit at predetermined pressure limits, auxiliary means for disturbing said pressure limits for a single cycle and thereafter automatically returning the pressure limits to normal, and manual manipulating means having means for rendering said auxiliary means effective for all succeeding successive cycles.

19. A control means including a pressure responsive means and means operated by said pressure responsive means for opening and closing an electric circuit, a loading means for normally controlling the movement of the pressure responsive means to normally cause the opening and closing of the electric circuit at predetermined pressure limits, a single cycle loading device for affecting the loading of said pressure responsive means to disturb said pressure limits for a single cycle and then automatically returning to normal the loading of said pressure responsive means, and manual manipulating means having means for rendering said single cycle loading device efiective for all succeeding successive cycles.

JESSE G. KING. 

